650 



Handbook of Nature-Study 



Sweet pea pod bursting in spiral. 



filaments disengages itself, and lying close to the style thrusts its anther 

 up into the point of the keel, below the stigma. But strange to say, one 

 lone, lorn stamen "flocks by itself" above the pistil, curving its anther up 

 stigma-ward. If we touch the point of the keel with the finger, up fly like 

 a jack-in-the-box the anthers splashing the finger with pollen; and if a 

 bee, in her search for nectar, alights on the wings at the very base of the 

 petals, up flies the pollen brush and daubs her with the yellow dust, which 



she may deposit on the stigma of 

 another flower. The interesting 

 part of this mechanism is the 

 brush near the tip of the style 

 below the stigma a veritable 

 broom, with splints all directed 

 upward. As the pollen is dis- 

 charged around it, the brush 

 lifts it up when the keel is pressed 

 down, and the stiff petals form- 

 ing the keel, in springing back to 

 place, scrape off the pollen and 

 plaster it upon the visitor. But 

 for all this elaborate mechanism, 

 sweet peas, of all flowers, are the 

 most difficult to cross-pollenate, 

 since they are so Mkely to receive 

 some of their own pollen during this process. 



The sweet-pea bud droops, a tubular calyx with its five-pointed lobes 

 forming a bell to protect it. Within the bud the banner petal clasps all in 

 its protecting embrace. 



After the petals fall, the young pod stands out from the calyx, the five 

 lobes of which are recurved and remain until the pod is well grown. As 

 the sweet pea ripens, all the moisture is lost and the pod becomes dry and 

 hard; through the dampness of dews at night and the sun's heat which 

 warps it by day, finally each side of the pod suddenly coils into a spiral, 

 flinging the seed many feet distant in different directions. 



LESSON CLXV 

 THE SWEET PEA 



Leading thought The sweet pea has its leaflets changed to tendrils, 

 which hold it to the trellis. Its flower is like that of the clover, the upper 

 petal forming the banner, the two side petals the wings, and the two 

 united lower petals the keel which protects the stamens and pistil. 



Method This should be a garden lesson. A study should be made of 

 the peas before they are planted, and their germination carefully watched. 

 Later, the method of climbing, the flower and the fruit should each be the 

 subject of a lesson. 



Observations on germination i. Soak some sweet peas over night; 

 split them the next morning. Can you see the little plant within ? 



2. Plant some of the soaked peas in cotton batting, which may be 

 kept moist. At what point does the sprout break through the seed cover- 

 ing? Do the root and leaf-shoot emerge at the same place, or at differ- 

 ent points? Which is the first to appear? 



